The researchers have identified factors that put a person at greater risk of COVID-related death after they have completed both doses of the primary COVID vaccination schedule and a booster dose.
For their research, published in JAMA Network Open, researchers from the Office for National Statistics (ONS); Public Health Scotland; the University of Strathclyde, Glasgow; and the University of Edinburgh used data from the ONS Public linked data set combining the 2011 Census of England and covering 80% of the population of England. The study population included 19,473,570 individuals aged 18-100 years (mean age 60.8 years, 45.2% men, 92.0% White individuals) living in England who had completed both doses of their primary vaccination schedule and had received their mRNA booster 14 days or more prior to Dec. 31, 2021. The outcome of interest was time to death involving COVID-19 occurring between Jan. 1 and March 16, 2022.
Prioritization of booster doses and COVID-19 treatments
The authors highlighted how it had become “critical” to identify risk factors associated with COVID-19 death in those who had been vaccinated and pointed out that existing evidence was “based on people who have received one or two doses of a COVID-19 vaccine and were infected by the Alpha or Delta variant”. They emphasized that establishing which groups are at increased risk of COVID-19 death after receiving a booster is crucial for the “prioritization of further booster doses and access to COVID-19 therapeutics.”
During the study period the authors found that there were 4,781 (0.02%) deaths involving COVID-19 and 58,020 (0.3%) deaths from other causes. Of those who died of coronavirus, the mean age was 83.3 years, and the authors highlighted how “age was the most important characteristic” associated with the risk of postbooster COVID-19 death. They added that, compared with a 50-year-old, the HR for an 80-year-old individual was 31.3 (95% confidence interval, 26.1-37.6).
They found that women were at lower risk than men with an HR of 0.52 (95% CI, 0.49-0.55). An increased risk of COVID-19 death was also associated with living in a care home or in a socioeconomically deprived area.
Of note, they said that “there was no association between the risk of COVID-19 death and ethnicity, except for those of Indian background”, who they explained were at slightly elevated risk, compared with White individuals. However, they explained how the association with ethnicity was “unclear and differed from previous studies”, with their findings likely to be due “largely to the pronounced differences in vaccination uptake” between ethnic groups in previous studies.
Dementia concern
With regard to existing health conditions the authors commented that “most of the QCovid risk groups were associated with an increased HR of postbooster breakthrough death, except for of congenital heart disease, asthma, and prior fracture.”
Risk was particularly elevated, they said, for people with severe combined immunodeficiency (HR, 6.2; 95% CI, 3.3-11.5), and they also identified several conditions associated with HRs of greater than 3, including dementia.
In July, Alzheimer’s Research UK urged the Government to boost the development and deployment of new dementia treatments having found that a significant proportion of people who died of COVID-19 in 2020 and 2021 were living with the condition. At the time, data published by the ONS of deaths caused by coronavirus in England and Wales in 2021 showed dementia to be the second-most common pre-existing condition.
David Thomas, head of policy at Alzheimer’s Research UK, said: “We’ve known for some time that people with dementia have been hit disproportionately hard during the pandemic, but this new data serves as a stark reminder of the growing challenge we face in tackling the condition, and the urgent need to address it.”
The authors of the new research acknowledged the study’s limitations, notably that only data for the population living in England who were enumerated in the 2011 Census of England and Wales was included.
However, subpopulations “remain at increased risk of COVID-19 fatality” after receiving a booster vaccine during the Omicron wave, they pointed out.
“The subpopulations with the highest risk should be considered a priority for COVID-19 therapeutics and further booster doses,” they urged.
A version of this article first appeared on Medscape UK.